ENERGY MANAGEMENT - THE DELAYED FLAP APPROACH.

The conventional jet transport instrument landing approach procedure requires high thrust settings for an extended time, with the accompanying community noise impact and relatively high fuel consumption. Significant reductions in both noise and fuel consumption can be gained through careful tailoring of the approach flight path and airspeed profile. The delayed-flap approach is initiated at a high airspeed and in a drag configuration that allows for low thrust. The aircraft is flown along the conventional ILS glide slope. Remaining at low thrust for reduced noise and fuel consumption, the flaps and landing gear are lowered at the appropriate times, so that the airspeed slowly decreases to the desired value at the desired point from touchdown. The delayed-flap approach 250 lb of fuel over the Reduced Flap approach, and has a 95 EPNdB noise contour only 43% as large.